I was going to fork out for a drill press, and some holesaws, so I could do my tube notching.
Then I read this thread, and the link at the top, and was going to use the template from that, but couldnt figure it out properly.
I read through the "Using a chopssaw method", from Pirate, and then I read the bit about using old toliet rolls to make the template.

Im currently doing my sliders, and I cut an extra piece so I could use it as a guide.
I used the grinder to get the piece notched to where I wanted it, then cut 1 toliet roll along the side, wrapped it around the piece of tube I had just cut, and marked the notch with a pen.
Thenit was as easy as cutting along the line, wrap the toliet roll template around the tube, mark the line, and hack into it with the grinder.

Pieces of tube notched, a small gap here and there, but it came up pretty good for what seems like a dodgy technique.